1. Field of the Invention
This invention relates to a magnetic recording method, in which magnetic information is recorded on a magnetic recording medium, such as a magnetic card, a form with magnetic stripes, or a magnetic ticket, at an appropriate current value, an apparatus therefor, and a device for determining a coercive force of a magnetic recording medium.
2. Description of Related Art
Ordinarily, magnetic cards include ones of two kinds with magnetic stripes being of different kinds. The one is a low coercive force magnetic card, on which magnetic information is recorded by means of a magnetic head with a small write current. The other is a high coercive force magnetic card, on which magnetic information is recorded by means of a magnetic head with a large write current.
In some cases, magnetic information cannot be written when a magnetic head writes the magnetic information on a low coercive force magnetic card at a large write current. Therefore, when the magnetic head reads the magnetic information, there can be generated a fact that it is not possible to detect an appropriate read voltage and realize the written information.
There is caused the same problem when a magnetic head writes magnetic information on a high coercive force magnetic card at a small write current.
Hereupon, the following techniques for determining a high coercive force magnetic card or a low coercive force magnetic card are present.
(1) While a head is moved relatively, writing is performed at a predetermined flux variation per predetermined length of magnetic stripes as a write current is increased within a preset range. The written magnetic stripes are read by a readout head. A comparison between a voltage value and a current value from the readout head is made to select a current value at that time in the case where the voltage value is in an allowable range. In the case where the voltage value is outside the allowable range, a range previously selected is changed at the time of writing and a process in which writing is again performed on the magnetic stripes is repeated, the written magnetic stripes are read, and a write current value is determined. Thereby, it is possible to determine a coercive force of magnetic stripes to write magnetic information on the magnetic stripes at an appropriate current value (see Japanese Patent document JP-A-2001-148101).
(2) There is proposed a magnetic information recording apparatus for determining a coercive force of a magnetic recording medium and performing recording while changing an intensity of magnetism applied on the magnetic recording medium in accordance with results of such determination to correspond to the coercive force of the magnetic recording medium. Magnetic recording media used for recording information include two kinds of ordinary tickets and season tickets. Information indicative of whether these tickets are high coercive force magnetic cards or low coercive force magnetic cards is written on these tickets. A readout head reads the information to determine whether a received ticket is a high coercive force magnetic card or a low coercive force magnetic card. Based on the results, an exciting current is set to a value suited to a coercive force of the ticket to perform magnetic recording (see Japanese Patent document JP-B-4-38045).
Also, the following is described as another measure. A small ordinary ticket is a high coercive force recording medium. A large season ticket is a low coercive force recording medium. Whether a ticket conveyed is an ordinary ticket or a season ticket is determined on the basis of a size of the ticket. In the case where a concerned ticket is a small one as results of the determination, information is written on the ticket at a high coercive force. Meanwhile, in the case where a concerned ticket is a large one as results of the determination, information is written on the ticket at a low coercive force. Thereby, magnetic recording is performed at an intensity of magnetism corresponding to a large or small coercive force of the ticket.
(3) A magnetic card reader reads and determines a coercive force of a magnetic card used. In this case, determination means for determining a coercive force of data tracks for recording of magnetic information is provided in the magnetic card reader, in which magnetic information of a magnetic card inserted into a card insertion port is reproduced or recorded by a magnetic head. And after a test data is recorded on data tracks of a magnetic card taken in, at a current corresponding to a low coercive force magnetic card, it is reproduced and the card is determined to be a low coercive force card in the case where the reproduced data corresponds to the test data (see Japanese Patent document JP-A-11-96506).
(4) A magnetic card reader reads and determines a coercive force of a magnetic card used. In this case, the magnetic card reader includes a plurality of magnetic heads provided corresponding to a plurality of tracks, which are formed on a magnetic card inserted into a card insertion port, to reproduce or record magnetic information on the plurality of tracks, the plurality of magnetic heads, respectively, serving to record or erase a data at a current of different predetermined values, and a coercive force determining unit for determining three or more kinds of coercive forces of data tracks through reproduction of recording and erasing results. For example, reproduction is performed after erasing is performed on a first track at a current of a first value, reproduction is performed after erasing is performed on a second track at a current of a second value, and a coercive force of a magnetic card is determined on the basis of the relationship between output levels of results of such reproduction and the first and second values (see Japanese Patent document JP-A-11-328604).
(5) There is proposed a method of determining a coercive force of a magnetic card used. In this case, the method, in which a magnetic head reproduces or records magnetic information formed on a low coercive force magnetic card or a high coercive force magnetic card inserted from a card insertion port, includes erasing a data of the inserted card at a current capable of erasing only a data of a low coercive force magnetic card, thereafter reproducing the data of the card, and determining the inserted card to be a low coercive force magnetic card in the case where the data has been destroyed. The destroyed state of the data is determined by the number of times of magnetization reversal of the reproduced data, or by non-recognition of a specific data (STX cord) recorded on a predetermined card (see Japanese Patent document JP-A-2000-155816).
(6) An operation of determining a magnetism coercive force can be omitted, a service life of an apparatus is extended, and the risk of data destruction due to wrong determination is avoided. Even when a magnetic card actually inserted is either of a high coercive force magnetic card and a low coercive force magnetic card, an operation of recording on the magnetic card is performed by performing again an operation of recording by the use of a small write current after an operation of recording by the use of a large write current so that predetermined magnetic information can be favorably written without determining whether a concerned magnetic card is either of the cards (see Japanese Patent document JP-A-2001-118206).
However, Japanese Patent document JP-A-2001-148101 involves a problem that a processing of determination takes much time since a magnetic card must be conveyed several times in order to determine an appropriate write current.
With the remaining Japanese Patent documents discussed above, it is possible to determine whether a kind of a magnetic card corresponds to a high coercive force or a low coercive force. A coercive force of a low coercive force magnetic card disperses in a particular, allowable region. However, a coercive force of a high coercive force magnetic card disperses in an unallowable region, in many cases. Therefore, an appropriate write current is in many cases different every high coercive force magnetic card.
Further, even when an appropriate write current at which writing is performed on respective magnetic cards is determined, whether a coercive force of a magnetic card is high or low, a coercive force, which is varied, cannot be measured.
Therefore, it is desired that appropriate write currents suited to respective magnetic cards be found. For example, it is conceivable that an appropriate write current suited to a coercive force of a magnetic card be found by writing magnetic information for determination of a coercive force on the magnetic card and reading the magnetic information thus written.
However, in this case, even when abnormality is involved in that magnetic information for determination of a coercive force, which is written on the magnetic card, determination of magnetism is done as it is, so that a normal coercive force is not obtained.